Is there anything eles that can cause nitrogen fixation?

Nitrogen fixation, any natural or industrial process that causes free nitrogen (N2), which is a relatively inert gas plentiful in air, to combine chemically with other elements to form more-reactive nitrogen compounds such as ammonia, nitrates, or nitrites.

Under ordinary conditions, nitrogen does not react with other elements. Yet nitrogenous compounds are found in all fertile soils, in all living things, in many foodstuffs, in coal, and in such naturally occurring chemicals as sodium nitrate (saltpetre) and ammonia. Nitrogen is also found in the nucleus of every living cell as one of the chemical components of DNA.

Nitrogen is fixed, or combined, in nature as nitric oxide by lightning and ultraviolet rays, but more significant amounts of nitrogen are fixed as ammonia, nitrites, and nitrates by soil microorganisms. More than 90 percent of all nitrogen fixation is effected by them. Two kinds of nitrogen-fixing microorganisms are recognized: free-living (non-symbiotic) bacteria, including the cyanobacteria (or blue-green algae) Anabaena and Nostoc and genera such as Azotobacter, Beijerinckia, and Clostridium; and mutualistic (symbiotic) bacteria such as Rhizobium, associated with leguminous plants, and various Azospirillum species, associated with cereal grasses.

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